Microplastics contamination in bivalves from the Daya Bay: Species variability and spatio-temporal distribution and human health risks

Beneath the surface: Exploring microplastic intricacies in Anadara granosa

Anadara granosa or blood cockles have been reported to be a candidate for biomonitoring agents due to their sedimentary nature and their nutrient uptake mechanisms. Yet, this bivalve is still regarded as a delicacy in Asian cuisine. Malaysia is the largest exporter of this sea product that contaminated cockles may also be experienced by the importing countries. However, the bioaccumulation of microplastics in A. granosa cultivated in Malaysia has not been extensively studied. It is crucial to comprehend the risk posed to humans by consuming A. granosa in their diet. Therefore, the purpose of this research is to investigate the levels of microplastic accumulation in A. granosa from major exporters in Peninsular Malaysia, to evaluate the associated risk of microplastics on the species, and to estimate daily human consumption of microplastics through the consumption of A. granosa. The abundance of microplastics was quantified through the use of a stereo microscope, and the polymer type was determined using FTIR and micro-FTIR. Findings from this investigation revealed that all samples of A. granosa were contaminated with microplastics, with the highest levels of accumulation found in bivalves collected from the west coast (0.26 ± 0.15 particles/g) of Peninsular Malaysia. Fragment and fiber microplastics, measuring between 0.05 and 0.1 mm in size, were found to be the most prevalent in A. granosa, with blue being the dominant identified colour and rayon being the most common polymer type. Microplastic risk assessment due to the presence of polyacrylate, polycarbonate (PC), and polymethyl methacrylate (PMMA) resulted in a high risk of contamination for A. granosa. It was further determined that the current estimated dietary intake (EDI) suggests that consumers of A. granosa uptake approximately 21.8-93.5 particles/person/year of microplastics. This study highlights that A. granosa accumulates microplastics, which could potentially result in bioaccumulation and biomagnification in humans through consumption.

Effects of chronic cold stress on tissue structure, antioxidant response, and key gene expression in the warm-water bivalve Chlamys nobilis

As ectothermic invertebrates, mollusks are regarded as good environmental indicator species for determining the adverse effects of climate change on marine organisms. In the present study, the effects of cold stress on the tissue structure, antioxidant activity, and expression levels of genes were evaluated in the warm-water noble scallop Chlamys nobilis by simulating natural seawater cooled down during winter from 17 °C to 14 °C, 12 °C, 10 °C, and 9 °C. Firstly, the gill was severely damaged at 10 °C and 9 °C, indicating that it could be used as a visually indicative organ for monitoring cold stress. The methylenedioxyamphetamine (MDA) content significantly increased with the temperatures decreasing, meanwhile, the antioxidant enzyme activities superoxide dismutase (SOD) and catalase (CAT) showed a similar pattern, suggesting that the scallop made a positive response. More importantly, 6179 genes related to low temperatures were constructed in a module-gene clustering heat map including 10 modules. Furthermore, three gene modules about membrane lipid metabolism, amino acid metabolism, and molecular defense were identified. Finally, six key genes were verified, and HEATR1, HSP70B2, PI3K, and ATP6V1B were significantly upregulated, while WNT6 and SHMT were significantly downregulated under cold stress. This study provides a dynamic demonstration of the major gene pathways' response to various low-temperature stresses from a transcriptomic perspective. The findings shed light on how warm-water bivalves can tolerate cold stress and can help in breeding new strains of aquatic organisms with low-temperature resistance.

Microplastics in retail shellfish from a seafood market in eastern Thailand: Occurrence and risks to human food safety

This study aimed to investigate the presence of microplastics in three economically essential shellfish species: green mussels, cockles and spotted babylon. The average abundance of microplastics ranged from 2.41 to 2.84 particles/g wet weight. The predominant shape was fiber, with colors ranging from black-grey to transparent. The size of the microplastics discovered was <1.0 mm. Polystyrene and polyethylene were the most detected types in mussels and cockles, while linen was the predominant type in spotted babylon. The Thai population's estimated annual intake (EAI) of microplastics through shellfish consumption ranged from 20.23 to 1178.42 particles/person/year. The potential human health risks were evaluated using the polymer hazard index (PHI), which led to risk categories III-IV. These findings, along with others from the literature, indicate that shellfish consumption may pose risks to human health, depending on the species consumed and the origin of the specimens.

Microplastics in rocky shore mollusks of different feeding habits: An assessment of sentinel performance

Microplastics (MPs) accumulation in rocky shore organisms has limited knowledge. This study investigated MPs accumulation in filter-feeding oysters, herbivorous limpets and carnivorous snails to assess their performance as sentinel species in the MPs trophic transfer. The samples were obtained along a contamination gradient in the Santos Estuarine System, Brazil. All three studied species showed MPs concentrations related to the contamination gradient, being the oysters the species that showed the highest levels, followed by limpets and snails (average of less and most contaminated sites of 1.06-8.90, 2.28-5.69 and 0.44-2.10 MP g-1, respectively), suggesting that MPs ingestion rates are linked to feeding habits. MPs were mainly polystyrene and polyacetal. The polymer types did not vary among sites nor species. Despite minor differences in percentages and diversity of size, shape, and color classes, the analyzed species were equally able to demonstrate dominance of small, fiber, transparent, black and blue MPs. Thus, oysters, limpets, and snails are proposed as sentinels of MPs in monitoring assessments.

Evaluation of the microplastics in bivalves and water column at Pantai Teluk Likas, North Borneo, Malaysia

Microplastics (MPs) are a pervasive pollutant in the marine environment. Pantai Teluk Likas in Sabah, Malaysia is one of the most visited beaches where tourism, recreational, and fisheries activities are high in this area. Hence, the area suffers from severe pollution, particularly from plastics. This study aims to quantify the microplastic composition in terms of color, shapes, and polymer types in marine bivalves (Anadara granosa, Glauconome virens, and Meretrix lyrata) and water column samples from Pantai Teluk Likas. All samples were digested using sodium hydroxide (NaOH) and incubated in the oven for at least 48 h. Serial filtration was done for each sample before they were observed under the dissecting microscope. The microplastics were identified and counted based on their physical attributes which were colors and shapes. The functional group of the polymers was determined using FTIR spectroscopy. Microplastics were found present in all samples collected. G. virens had the highest abundance of microplastics at 113.6 ± 6.5 particles/g followed by M. lyrata at 78.4 ± 3.7 particles/g. On the contrary, A. granosa had the least microplastics with an abundance of 24.4 ± 0.6 particles/g. Meanwhile, 110.0 ± 36.2 particles/L of microplastics were found in water column samples from Pantai Teluk Likas. Based on the analysis, fibers were the most common shape in bivalves, while fibers and films were common in the water column. In terms of colors, black, blue, and red were a few of the most abundant colors observed in both samples. The most common polymer detected in all bivalve species and water column samples is polycarbonate (PC), followed by polymethyl methacrylate (PMMA). Future study that focuses on the correlation between microplastic abundance in the marine biota and the water column is recommended to better understand microplastic availability and exposure.

Distribution of microplastics in seafloor sediments and their differential assimilation in nearshore benthic molluscs along the south-west coast of India

Spatial and temporal distribution of microplastics (MPs) in the nearshore seafloor sediments along the Southwest coast of India and their patterns of accumulation in selected infaunal and epibenthic molluscs with diverse feeding strategies were investigated. Along the 300-km coastal stretch, which is one of the most productive and biodiversity rich regions of the eastern Arabian Sea, notable levels of MP contamination in both sediment (617.7 items/kg dry weight) and molluscs (5.39 items/g) was recorded. The concentration of MPs in sediments also varied seasonally, with a higher prevalence during the post-monsoon season. Among the four molluscan groups studied, the highest MP abundance was recorded among scavenging gastropod Pseudominolia biangulosa (9.13 items/g), followed by microcarnivore scaphopod Tesseracme quadrapicalis (5.96 items/g). In comparison, the suspension feeding bivalve, Anadara hankeyana and deposit feeding clam Jitlada philippinarum had lesser accumulation of MPs (2.98 items/g and 3.50 items/g respectively). The majority of MPs in sediments and within molluscs were less than 250 μm in size (89.14%) and were predominantly fibres and fragments. Chemical characterisation of MPs revealed eleven types of polymers dominated by polyethylene (PE) and polypropylene (PP). Present study identified positive correlations between ingested MP polymers and the feeding strategies of molluscs. Higher values for the ecological risk assessment indices (PHI, PLI and PERI) in most of the stations indicated the severity of plastic pollution in the region. Molluscs being a major contributor to the benthic food web is also a connecting link to higher trophic levels. Hence understanding the specificity in the MPs accumulation pattern within this group has far reaching significance in utilizing them as potential bioindicators for pollution studies in marine ecosystems.

Distribution and characteristics of microplastics in 16 benthic organisms in Haizhou Bay, China: Influence of habitat, feeding habits and trophic level

Microplastics (MPs) are widely found in the ocean and cause a serious risk to marine organisms. However, fewer studies have been conducted on benthic organisms. This study conducted a case study on the pollution characteristics of MPs on 16 marine benthic organisms in Haizhou Bay, and analyzed the effects of habitat, trophic level, and feeding mode on the MPs pollution characters. The results showed that MPs were detected in all 16 organisms with an average abundance of 8.84 ± 9.14 items/individual, which is in the middle-high level in the international scale. Among the detected MPs, the main material was cellophane. This study showed that benthic organisms can be used as indicator organisms for MPs pollution. MPs in organisms can be affected by their habitat, trophic level, and feeding mode. Comprehensive analysis of MPs in benthic organisms will contribute to fully understand the characterization and source resolution of MPs pollution.

The occurrence of pollutants in organisms and water of inland mariculture systems: Shrimp aquaculture is a procession of Microplastics accumulation

Microplastics (MPs) pollution in the ocean was widely concerned, but the current study on MPs pollution in the mariculture system is relatively lacking. This study researched the MPs pollution characteristics in water and shrimp at different stages of the pond and industrial aquaculture. The study shows that in the same aquaculture stage, MPs abundance in shrimp and water in pond aquaculture mode is higher than that in industrial aquaculture mode. The MPs pollution characteristics in shrimp and water show significant consistency. The hazard index of MPs in pond water and industrial models are 122 (Level Ⅲ) and 540 (Level Ⅲ), respectively, indicating that industrial aquaculture models may suffer from more severe MPs stress. The aquaculture period and mode significantly affected the MPs abundance of water and shrimp, but there was no interaction between the aquaculture period and mode. MPs abundance in shrimp show a significant relationship with the length of crustacean and weight. This study further enhanced the understanding of MPs pollution of water and organisms in different aquaculture modes at different stages, and warned MPs is widely spread in mariculture systems.

Microplastics aggravate the bioaccumulation and corresponding food safety risk of antibiotics in edible bivalves by constraining detoxification-related processes

Characterized by a sessile filter-feeding lifestyle, commercial marine bivalves inhabiting pollution-prone coastal areas may accumulate significant amounts of pollutants, such as antibiotic residues, in their soft tissues and thus pose a potential threat to the health of seafood consumers. Microplastics are another type of emerging pollutant that are prevalent in coastal areas and have been reported to interact with common antibiotics such as enrofloxacin (ENR) and trimethoprim (TMP). Nevertheless, little is known about the impacts of MPs on the accumulation and corresponding food safety risk of antibiotics in edible bivalve species. Taking the frequently detected ENR, TMP, and polystyrene (PS)-MPs as representatives, the accumulation of above-mentioned antibiotics in three commercial bivalves with or without the copresence of MPs was assessed. In addition, the corresponding food safety risks of consuming antibiotic-contaminated bivalves were evaluated. Moreover, the impacts of these pollutants on detoxification-related processes were analyzed using the thick-shell mussel as a representative. Our results demonstrated that blood clams (Tegillarca granosa), thick-shell mussels (Mytilus coruscus), and Asiatic hard clams (Meretrix meretrix) accumulated significantly higher amounts of antibiotics in their bodies under antibiotic-MP coexposure scenarios. Although based on the target hazard quotients (THQs) and the margins of exposure (MoEs) obtained, the direct toxic risks of consuming ENR- or TMP-contaminated bivalves were negligible, the TMP residue accumulated in TMP-MP-coexposed mussels did surpass the maximum residue limits (MRLs) of the corresponding National Food Safety Standard of China, suggesting that other forms of potential risks should not be ignored. In addition, it was shown that the detoxification, energy provision, and antioxidant capacities of the thick-shell mussels were significantly hampered by exposure to the pollutants. In general, our data indicate that MPs may aggravate the accumulation and corresponding food safety risk of antibiotics in edible bivalves by disrupting detoxification-related processes, which deserves closer attention.

Microplastic pollution and ecological risk assessment of Yueqing Bay affected by intensive human activities

Microplastics (MPs) are a widespread environmental problem posing ecological risks in the ocean. We investigated the abundance, spatial distribution, characteristics and ecological risks of MPs in surface seawater, sediments and organisms in Yueqing Bay, China. MPs were detected in both environmental media and organisms. The overall abundance (0.24 items/m3 seawater, 6.13 items/kg dry sediment, 0.77 items/individual in organisms) was low to medium compared with other coastal areas. The MPs were mainly derived from the high-intensity mariculture and shipping in the bay, as well as industrial and human activities along the surrounding coast. The abundance of MPs in water of the left (western) bay (0.39 items/m3) was considerably higher than that of the right (north-eastern) bay (0.07 items/m3) due to the different levels of population and economic development on the left and right coasts. The ecological risk assessment showed generally low to medium risk from MPs pollution in Yueqing Bay, with higher ecological risk index (H) and potential ecological hazards (RI) of MPs polymers in water samples. These data emphasize the need for timely and effective action to reduce the contribution of intensive human activities to MPs pollution and provide information for further ecotoxicological studies, pollution control, and policy development of MPs.

Characteristics and potential human health risks of microplastics identified in typical clams from South Yellow Sea Mudflat

The ingestion of clams (Meretrix) with microplastics (MP) contamination could pose potential risk to human health. The characteristics and potential risks of MP identified in wild-clam and farm-clam from South Yellow Sea Mudflat were studied comprehensively in this paper. The results indicated that MP were identified in both wild-clam (3.4-21.3 items/individual, 2.11-10.65 items/g) and farm-clam (1.3-20.8 items/individual, 0.62-8.67 items/g) among 21 sampling sites along South Yellow Sea Mudflat. The MP abundance of clams from marine estuarine or coast ports were significantly higher than those from purely marine coast mudflat, implying that environmental habitats played an important role on MP characteristics. MP abundance were significantly and positively related to shell length, shell height, shell width and soft tissue wet weight by Pearson test, suggesting the bigger the shell, there existed more MP abundance. Among MP in wild-clams and farm-clams, fragment, fiber were most abundant MP shapes, most MP's sizes were lower than 0.25 mm, the predominant colors were black, red, blue and transparent, chlorinated polyethylene (CPE) was the major polymer. Additionally, estimated dietary intake (EDI) of MP for adults via consumption of wild-clam and farm-clam were 1123.33 ± 399.97 and 795.07 ± 326.72 items/kg/year, respectively, suggesting EDI values of wild-clams were higher than those of farm-clams, and MP intake via wild-clam consumption were more than that via farm-clam consumption. The polymer risk indexes (PRI) of MP in total tissue and digestive system for wild-clam were 1297.8 ± 92.15 (hazard level: IV ~ V), 1038 ± 69.55 (IV ~ V), respectively, while PRI of MP in total tissue and digestive system for farm-clam were 979.92 ± 75.45 (III ~ IV), 735 ± 47.78 (III ~ IV), respectively, implying that PRI and hazard level of MP from wild-clam were higher than those from farm-clam, and the potential risks would decrease greatly when digestive systems of clams are removed during ingestion.

Microplastics in marine mussels, biological effects and human risk of intake: A case study in a multi-stressor environment

This study documented seasonal levels of microplastics (MPs) and biomarkers (condition index, neurotoxicity, energy, oxidative stress) in mussels (Mytilus galloprovincialis), and water physico-chemical parameters in the Douro estuary (NE Atlantic coast), and estimated the human risk of MP intake (HRI) through mussels. Mussel stress was determined through the Integrated Biomarker Response (IBR). HRI was estimated from mussel MP concentrations and consumer habits. MPs were mainly micro-fibres (72 %) with varied chemical composition. Seasonal MP means (±SEM) in mussels ranged from 0.111 ± 0.044 (spring) to 0.312 ± 0.092 MPs/g (summer). Seasonal variations of mussel stress (IBR: 1.4 spring to 9.7 summer) and MP concentrations were not related. MeO-BDEs, PBDEs, temperature, salinity and other factors likely contributed to mussel stress variation. HRI ranged from 2438 to 2650 MPs/year. Compared to the literature, MP contamination in mussels is low, as well as the human risk of MP intake through their consumption.

Microplastic accumulation in bivalves collected from different coastal areas of Vietnam and an assessment of potential risks

Microplastic (MP) pollution is an emerging problem in many areas around the world and in coastal areas of Vietnam, requiring more studies dedicated to the accumulation of this pollutant in the food chain as well as its potential risk to human health. This study investigated MP levels in tissues of five common bivalve species collected from aquaculture areas along the coast of Vietnam. MPs were found in all bivalve samples, with average values of 10.84 ± 2.61 items/individual or 2.40 ± 1.34 items/g wet weight. Impacts of feeding habits of bivalves showed influences on MP abundance in the samples. Fibers were the dominant shape of MPs recorded, most of which accumulated in the gills and digestive glands of all bivalve samples, with the majority falling within the size range of 300-2000 µm. MPs found in all studied species had relatively similar chemical compositions, mainly composed of polypropylene (PP) and polyethylene (PE). In this study, a diverse diet consisting of different bivalve species and detailed data on the consumption rate of these species were used to assess the human health risk of MPs dedicated to the coastal communities of Vietnam. The results suggested a significant part of MP uptake by human could be via bivalve consumption, in which removing viscera and proper depuration should be applied prior to eating, thereby reducing the risk.

Microplastics in aquaculture systems: Occurrence, ecological threats and control strategies

With the intensification of microplastic pollution globally, aquaculture environments also face risks of microplastic contamination through various pathways such as plastic fishing gear. Compared to wild aquatic products, cultured aquatic products are more susceptible to microplastic exposure through fishing tackle, thus assessing the impacts of microplastics on farmed species and human health. However, current research on microplastic pollution and its ecological effects in aquaculture environments still remains insufficient. This article comprehensively summarizes the pollution characteristics and interrelationships of microplastics in aquaculture environments. We analyzed the influence of microplastics on the sustainable development of the aquaculture industry. Then, the potential hazards of microplastics on pond ecosystems and consumer health were elucidated. The strategies for removing microplastics in aquaculture environments are also discussed. Finally, an outlook on the current challenge and the promising opportunities in this area was proposed. This review aims to evaluate the value of assessing microplastic pollution in aquaculture environments and provide guidance for the sustainable development of the aquaculture industry.

Recent Study of Separation and Identification of Micro- and Nanoplastics for Aquatic Products

Micro- and nanoplastics (MNPs) are polymeric compounds widely used in industry and daily life. Although contamination of aquatic products with MNPs exists, most current research on MNPs focuses on environmental, ecological, and toxicological studies, with less on food safety. Currently, the extent to which aquatic products are affected depends primarily on the physical and chemical properties of the consumed MNPs and the content of MNPs. This review presents new findings on the occurrence of MNPs in aquatic products in light of their properties, carrier effects, chemical effects, seasonality, spatiality, and differences in their location within organisms. The latest studies have been summarized for separation and identification of MNPs for aquatic products as well as their physical and chemical properties in aquatic products using fish, bivalves, and crustaceans as models from a food safety perspective. Also, the shortcomings of safety studies are reviewed, and guidance is provided for future research directions. Finally, gaps in current knowledge on MNPs are also emphasized.

Preliminary survey on the occurrence of microplastics in bivalve mollusks marketed in Apulian fish markets

Microplastics (MPs) are a relevant threat to food safety because they are ingested by humans through various foods. Bivalves are at high risk of microplastic contamination due to their filter-feeding mechanism and pose a risk to consumers as they are ingested whole. In this work, microplastics were detected, quantified, identified, and classified in samples of mussels (Mytilus galloprovincialis) and oysters (Crassostrea gigas) marketed in the Apulia region. The total number of plastic debris was 789 particles in the mussel samples and 270 particles in the oyster samples, with size ranging from 10 to 7350 μm. Fragments with size within the category of 5-500 μm were the predominant findings in both species, with blue as the predominant color in mussels and transparent in oysters; most of the debris was polyamide and nylon polymers in the mussels and chlorinated polypropylene in the oysters. These results show that mussel and oyster samples purchased at fish markets are contaminated with microplastics. The sources may be diverse and further studies are needed to assess the impact of the marketing stage on microplastic contamination in bivalves to better define the human risk assessment associated with microplastic exposure from bivalves consumption.

Microplastic contamination in edible clams from popular recreational clam-digging sites in Hong Kong and implications for human health

The ubiquitous presence of microplastics in edible bivalves and the human health risks associated with bivalve consumption have raised public concerns. Farmed and market-sold bivalves have received the most attention, while wild bivalves have received much less scrutiny. In the present study, 249 individuals were examined across six wild clam species from two popular recreational clam-digging sites in Hong Kong. Of the clams, 56.6 % contained microplastics, with an average abundance of 1.04 items/g (wet weight) and 0.98 items/individual. This resulted in an estimated annual dietary exposure of 14,307 items per Hong Kong resident. Moreover, the potential microplastic risks for humans associated with wild clam consumption were assessed using the polymer hazard index, and the results indicated a medium degree of risk, indicating that exposure to microplastics through wild clam consumption is inevitable and poses a potential health threat to humans. Further research is needed to facilitate a better understanding of the widespread occurrence of microplastics in wild bivalves, and further refinements of the risk assessment framework can hopefully allow a more accurate and holistic health risk assessment for microplastics.

The adverse impact of microplastics and their attached pathogen on hemocyte function and antioxidative response in the mussel Mytilus galloprovincialis

Microplastics (MPs) are widely distributed in marine environments, and they are easily attached by various microorganisms, including pathogenic bacteria. When bivalves mistakenly eat MPs, pathogenic bacteria attached to MPs enter their bodies through the Trojan horse effect, causing adverse effects. In this study, the mussel Mytilus galloprovincialis was exposed to aged polymethylmethacrylate MPs (PMMA-MPs, 20 μm) and Vibrio parahaemolyticus attached to PMMA-MPs to explore the effect of synergistic exposure by measuring lysosomal membrane stability, ROS content, phagocytosis, apoptosis in hemocytes, antioxidative enzyme activities and apoptosis-related gene expression in gills and digestive glands. The results showed that MP exposure alone did not cause significant oxidative stress in mussels, but after long-term coexposure to MPs and V. parahaemolyticus, the activities of antioxidant enzymes were significantly inhibited in the gills of mussels. Both single MP exposure and coexposure will affect hemocyte function. Coexposure can induce hemocytes to produce higher ROS, improve phagocytosis, significantly reduce the stability of the lysosome membrane, and induce the expression of apoptosis-related genes, causing apoptosis of hemocytes compared with single MP exposure. Our results demonstrate that MPs attached to pathogenic bacteria have stronger toxic effects on mussels, which also suggests that MPs with pathogenic bacteria might have an influence on the immune system and cause disease in mollusks. Thus, MPs may mediate the transmission of pathogens in marine environments, posing a threat to marine animals and human health. This study provides a scientific basis for the ecological risk assessment of MP pollution in marine environments.

Binational survey using Mytilus galloprovincialis as a bioindicator of microplastic pollution: Insights into chemical analysis and potential risk on humans

Microplastic (MP) contamination in edible mussels has raised concerns due to their potential risk to human health. Aiming to provide valuable insights regarding the occurrence, physicochemical characteristics, and human health implications of MP contamination, in the present study, two nationwide surveys of MP contamination in mussels (Mytilus galloprovincialis) were conducted in Morocco and Tunisia. The results indicated that MP frequency ranged from 79 % to 100 % in all the analyzed samples. The highest MP density was detected in mussels from Morocco (gills "GI": 1.88 MPs/g ww^-1; digestive glands "DG": 0.92 MPs/g ww^-1) compared to mussels of Tunisia (GI: 1.47 MPs g^{- 1}; DG: 0.79 MPs g^{- 1}). No significant differences in MP density were found between the two organs (GI and DG) for both countries. MPs were predominantly blue and black fibers, and smaller than 1000 μm. Seven polymeric types were identified, of which PET, PP, and PE were the most abundant, accounting for >87 % of all samples. Scanning Electron Microscopy (SEM) coupled with Energy dispersive X-ray (EDX) showed that most MPs have noticeable signs of weathering and inorganic components on their surface. The highest MP daily intake was found in children, while the lowest was estimated in women and men. Moreover, the annual dietary exposure of MPs through mussel consumption was estimated to be 1262.17 MPs/year in Morocco and 78.18 MPs/year in Tunisia. The potential risk assessment of MPs in mussels based on the polymer hazard index (PHI) was estimated in the high-risk levels, implying that MPs may pose health risks to humans. Overall, this research suggests that the consumption of mussels represents a considerable MP exposure route for the Moroccan and Tunisian populations.

Exploring the Potential Hormonal Effects of Tire Polymers (TPs) on Different Species Based on a Theoretical Computational Approach

Tire polymers (TPs) are the most prevalent type of microplastics and are of great concern due to their potential environmental risks. This study aims to determine the toxicity of TPs with the help of molecular-dynamics simulations of their interactions with receptors and to highlight the differences in the toxicity characteristics of TPs in different environmental media (marine environment, freshwater environment, soil environment). For this purpose, five TPs—natural rubber, styrene–butadiene rubber (SBR), butadiene rubber, nitrile–butadiene rubber, and isobutylene–isoprene rubber—were analyzed. Molecular-dynamics calculations were conducted on their binding energies to neurotoxic, developmental, and reproductive receptors of various organisms to characterize the toxic effects of the five TPs. The organisms included freshwater species (freshwater nematodes, snails, shrimp, and freshwater fish), marine species (marine nematodes, mussels, crab, and marine fish), and soil species (soil nematodes, springtails, earthworms, and spiders). A multilevel empowerment method was used to determine the bio-toxicity of the TPs in various environmental media. A coupled-normalization method–principal-component analysis–factor-analysis weighting method—was used to calculate the weights of the TP toxicity (first level) categories. The results revealed that the TPs were the most biologically neurotoxic to three environmental media (20.79% and 10.57% higher compared with developmental and reproductive toxicity, respectively). Regarding the effects of TPs on organisms in various environmental media (second level), using a subjective empowerment approach, a gradual increase in toxicity was observed with increasing trophic levels due to the enrichment of TPs and the feeding behavior of organisms. TPs had the greatest influence in the freshwater-environment organisms according to the subjective empowerment approach employed to weight the three environmental media (third level). Therefore, using the minimum-value method coupled with the feature-aggregation method, the interval-deflation method coupled with the entropy-weighting method, and the standard-deviation normalization method, the three toxicity characteristics of SBR in three environmental media and four organisms were determined. SBR was found to have the greatest impact on the overall toxicity of the freshwater environment (12.38% and 9.33% higher than the marine and soil environments, respectively). The greatest contribution to neurotoxicity (26.01% and 15.95% higher than developmental and reproductive toxicity, respectively) and the greatest impact on snails and shrimp among organisms in the freshwater environment were observed. The causes of the heterogeneity of SBR’s toxicity were elucidated using amino-acid-residue analysis. SBR primarily interacted with toxic receptors through van der Waals, hydrophobic, π-π, and π-sigma interactions, and the more stable the binding, the more toxic the effect. The toxicity characteristics of TMPs to various organisms in different environments identified in this paper provide a theoretical basis for subsequent studies on the prevention and control of TMPs in the environment.

Occurrence of antibiotic resistance genes carried by plastic waste from mangrove wetlands of the South China Sea

Plastic waste can carry organisms such as bacterial pathogens and antibiotic resistance genes (ARGs) over long distances. However, only few studies have been conducted on the occurrence of ARGs in plastic waste from mangrove wetlands. This study evaluated the distribution characteristics and ecological risks of plastic waste from mangroves in the coastal areas of the South China Sea. The correlation between anthropogenic activity levels and abundance of ARGs in mangroves was evaluated. Transparent and white were the common colors of plastic waste in mangroves. The main shapes of plastic waste were foam and film. The predominant types of plastic waste order were as follows: polyethylene (30.18 %) > polypropylene (27.51 %) > polystyrene (23.59 %). The living area (LA) mangroves had the highest polymer hazard and pollution load indices of 329.09 and 10.03, respectively. The abundance of ARGs (5.08 × 10⁸ copies/g) on the plastic surface in LA mangroves was significantly higher than that of the other mangrove areas. Furthermore, there was a significant correlation between ARGs and intI1 on the plastic surface in mangroves. Correlation analysis between the ARGs and intI1 showed that most of the ARGs were correlated with intI1 except for msbA. In LA mangroves, sociometric and environmental factors showed significant correlations with the absolute abundances of the four ARGs and intI1, indicating that anthropogenic activities may lead to changes in the amount of ARGs on plastic surfaces. Furthermore, the ARG storage of plastic waste from different mangroves was as follows: protected areas (3.12 × 10¹⁷ copies) > living areas (2.99 × 10¹⁷ copies) > aquaculture pond areas (2.88 × 10¹⁷ copies). The higher ARG storage of LA mangroves, with the smallest area, greatly increased its ecological risk. The results of this study can provide basic data for processes that influence the distribution of plastic waste and ARGs in mangroves.

Microplastic load of benthic fauna in Jiaozhou Bay, China

The prevalence of microplastic pollution in the ocean has caused widespread concern. Many studies have focused on the occurrence of microplastics in the marine environment and organisms, but the fate of microplastics in the ocean is still unclear, and the factors affecting the distribution of microplastics have not yet been consistently concluded. The aims of this study were to estimate the load of microplastics in benthic organisms as a temporary storage and to analyze the factors affecting microplastic ingestion by benthic organisms. For the purpose of this study, the benthic organisms in Jiaozhou Bay, China, were collected quarterly and were divided into the following six groups: polychaetes, mollusks, crustaceans, echinoderms, fish, and others. We concluded that the microplastic abundance in the benthos in Jiaozhou Bay was 1.00 ± 0.11 items/ind. (15.5 ± 3.5 items/g). The total load of microplastics in the benthic fauna in the bay with an area of 374 km² was estimated to be 36.4 kg. On an individual basis, the fish contained significantly more microplastics than the other taxa. Furthermore, the characteristics of the microplastics in the benthic organisms were mainly fibrous, black, polyethylene, and <500 μm in size. In addition, the microplastic ingestion by benthic organisms was regulated by multiple factors, including biological characteristics and the environment. The masses of the organisms, the ambient seawater and sediment, and the spatial variations all influenced the microplastic ingestion by the organisms. The results of this study demonstrate that benthic organisms are an important storage for microplastics as they transferred through the ocean, and they provide an unbiased comparison of microplastic pollution among multiple organisms and the relevant pollution factors.

A review of microplastic pollution in aquaculture: Sources, effects, removal strategies and prospects

As microplastic pollution has become an emerging environmental issue of global concern, microplastics in aquaculture have become a research hotspot. For environmental safety, economic efficiency and food safety considerations, a comprehensive understanding of microplastic pollution in aquaculture is necessary. This review outlines an overview of sources and effects of microplastics in aquaculture. External environmental inputs and aquaculture processes are sources of microplastics in aquaculture. Microplastics may release harmful additives and adsorb pollutants in aquaculture environment, cause deterioration of aquaculture environment, as well as cause toxicological effects, affect the behavior, growth and reproduction of aquaculture products, ultimately reducing the economic benefits of aquaculture. Microplastics entering the human body through aquaculture products also pose potential health risks at multiple levels. Microplastic pollution removal strategies used in aquaculture in various countries are also reviewed. Ecological interception and purification are considered to be effective methods. In addition, strengthening aquaculture management and improving fishing gear and packaging are also currently feasible solutions. As proactive measures, new portable microplastic monitoring system and remote sensing technology are considered to have broad application prospects. And it was encouraged to comprehensively strengthen the supervision of microplastic pollution in aquaculture through talent exchange and strengthening the construction of laws and regulations.

Expanded polystyrene buoys as an important source of hexabromocyclododecanes for aquatic ecosystem: Evidence from field exposure with different substrates

The production and use of hexabromocyclododecanes (HBCDs) have been strictly limited due to their persistence, toxicity and bioaccumulation. However, the release of HBCDs from related products and wastes would continue for a long time, which may cause many environmental problems. In this study, we investigated the occurrence and distribution of HBCDs and microplastics (MPs) in aquatic organisms inhabiting different substrates. HBCDs were measurable in the seawater, sediment, expanded polystyrene (EPS) substrates and organism samples. Mostly, the concentrations of HBCDs in organisms inhabiting EPS buoys were significantly higher than those of the same species inhabiting other substrates. Meanwhile, the diastereomeric ratio (α/γ) of HBCDs in organisms inhabiting EPS buoys was closer to that in EPS buoys. The fugacity values of HBCDs in EPS buoys were much higher than those in other media, implying that HBCDs can be transferred from EPS buoys to other media. Additionally, MPs derived from EPS buoys would be mistaken as food and ingested by aquatic organisms. The transfer of HBCDs from EPS buoys to aquatic organisms can be achieved by aqueous and dietary exposures. In combination, the contribution of MP ingestion to HBCDs for aquatic organisms should be very limited. These results supported EPS buoys as an important source of HBCDs for the aquatic ecosystem. To effectively control HBCDs pollution, it is necessary to discontinue or reduce the use of EPS buoys.

The occurrence, speciation, and ecological effect of plastic pollution in the bay ecosystems

Bay is a unique part of the ecosystem, acting as the intersection for marine and terrestrial systems and hosting diverse biological organisms. The ubiquitous application of plastics has resulted in a massive amount of plastic waste released and accumulated in the bay ecosystem, posing significant ecological effects. Thus, thoroughly understanding plastic pollution's occurrence, speciation, and ecological effect in the bay ecosystems is of vital importance. We conducted a comprehensive review on the sources and distribution of plastics in the bay ecosystem, and the associate ecological effects, from individual toxicity to trophic transfer in ecosystems. Among bay areas around the world, the concentrations of microplastics vary from 0.01 to 3.62 × 10⁵ item/m³ in seawater and 0 to 6.75 × 10⁵ item/kg in sediment. Small-sized plastic particles (mostly <2 mm) were widely reported in bay organisms with the concentration range of 0 to 22.5 item/ind. Besides, the toxicity of plastics on marine organisms has been documented in terms of mortality, growth, development, reproduction, enzyme activity and transcription. Since abundance of small plastic particles (e.g., micro- and nano-scale) is far greater than large plastic debris in the bay ecosystems, in-depth risk assessment of small-sized plastics needs to be conducted under environmentally realistic conditions. Our review could provide a better understanding on the occurrence, speciation, and ecological effect of plastic pollution in the bay ecosystems.

Is Wild Marine Biota Affected by Microplastics?

The present review provides detailed information on the adverse effects of MPs on wild marine organisms, including tissue damage, fish condition, oxidative stress, immune toxicity, and genotoxicity. A bibliometric analysis was carried out on CiteSpace (version 6.1.R3) (Drexel University, Philadelphia, PA, USA) to verify how many papers studied the effects on wild marine species. The results showed a total of 395 articles, but only 22 really presented data on the effects or impacts on marine biota, and of these, only 12 articles highlighted negative effects. This review shows that the observed effects in wild organisms were less severe and milder than those found in the experimental conditions. The knowledge of negative effects caused by direct ingestion of microplastics in wild animals is still limited; more efforts are necessary to fully understand the role of MPs and the adverse effects on wild marine organisms, the ecosystem, and human health.

Microplastics in personal care products: Exploring public intention of usage by extending the theory of planned behaviour

Microplastics, artificial plastic particles with a particle size of <5 mm, have attracted considerable attention due to their potential negative impacts on the social economy, ecological environment, and human health. An important direct source of microplastics (i.e., microbeads in cosmetics) is scrub particles from personal care products, such as cosmetics and toothpaste. Therefore, it is necessary to understand consumers' perceptions and behaviours regarding these products, which can help reduce the emission of microplastics at the source. The purpose of this study is to quantitatively analyse the impact factors and interaction mechanisms of the public behavioural intention of reducing the use of personal care and cosmetic products containing microplastics through the expanded theory of planned behaviour (TPB) model. We conducted random face-to-face interviews with 496 respondents in Shanghai, China. The results show that (1) attitude has the most powerful positive influence on behavioural intention, followed by perceived behavioural control and environmental concern, whereas there is no significant direct influence of subjective norms, environmental education, and behavioural experience; (2) subjective norms have an indirect influence on behavioural intention through attitude and perceived behavioural control; and (3) environmental education and behavioural experience both have an indirect impact on behavioural intention through attitude. Practical and effective policy implications are proposed for the government to reduce microplastic pollution based on the results of this article.